1. Field of the Invention
The present invention relates to a display device, and more particularly, to a touch screen display.
2. Description of the Related Art
A touch screen display is an advanced input device which may be substituted for a keyboard and a mouse. In the touch screen display, a touch screen is mounted on a liquid crystal panel, and a user touches the touch panel to conduct a desired operation. The touch screen display enables the user to conduct institutive operations under a Graphic User Interface (“GUI”) environment (one example of which is the Windows™ operating system), and it may be widely used in computer-aided training and simulation applications, office automation applications, education applications, and game applications.
Such a touch screen display typically includes a liquid crystal panel for displaying image information, a touch panel mounted on the liquid crystal panel, a controller, a device driver and application software.
The liquid crystal panel includes a common electrode display plate having a common electrode, and a thin film transistor (“TFT”) display plate having a thin film transistor array disposed thereon. The common electrode display plate and the TFT display plate are disposed opposite to each other and bonded to each other by a seal line interposed between the two display plates. A liquid crystal layer is formed in a space between the two display plates. As such, the liquid crystal panel includes the two display plates (the common electrode display plate and the TFT display plate) and the liquid crystal layer interposed between the two display plates. A voltage applied to the electrodes reorders the liquid crystal molecules of the liquid crystal layer, and thus the amount of light transmitted through the liquid crystal layer is controlled. Thus, a desired image is displayed. The liquid crystal panel is a non-luminous element, and thus a backlight unit for supplying light is disposed on a rear side of the TFT display plate. The amount of light being emitted from the backlight unit and transmitted through the liquid crystal layer is controlled in accordance with the alignment state of the liquid crystal molecules.
The touch panel includes two substrates arranged to be opposed to each other, upper and lower conductive layers individually formed respectively on the two substrates, and a plurality of spacers interposed between the two substrates. If a user touches a specific point using his/her finger or a pen, the upper and lower conductive layers are brought into electrical contact with each other at the specific point, and positional information is acquired.
Such a touch screen display is basically used for a Personal Digital Assistant (“PDA”), and in recent years, it is mounted on a portable communication device (for example, a mobile phone).
In the known touch screen display in which a touch panel is mounted on the liquid crystal panel to acquire positional information, the entire display device is large in size, which makes it difficult for the user to carry the display device. For this reason, there is a need for a touch screen display that is compact and light-weight and that can be provided by a simple manufacturing process.